| 摘要 |
PURPOSE: A communication terminal having mixed cellular phone and radio functions is provided to share an RF(Radio Frequency) circuit between a cellular part and a radio part, so that the terminal is miniaturized. CONSTITUTION: In a transmission unit(210) and a receiving unit(250), amplifiers such as a drive amplifier(219), a power amplifier(220) and an LNA(Low Noise Amplifier)(252), and frequency converters such as an up-converter(214) and a down-converter(257) are shared by a cellular phone and a radio. The cellular phone uses a full-duplex system in which an Rx frequency and a Tx frequency are different each other, while the radio uses a half-duplex system in which an Rx frequency is equal to a Tx frequency. An antenna switch(230) is for selecting the full-duplex system or the half-duplex system to share an RF transceiving circuit in the cellular phone and the radio. And a local oscillator(270) is controlled using a programmable PLL(Phase Locked Loop)(271) to generate local oscillating frequencies corresponding to each frequency area. And the local oscillating frequencies are applied to the up-converter(214) of the transmission unit(210) and the down-converter(257) of the receiving unit(250).
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